A counterweight is mounted on a construction machine such as a hydraulic shovel or a crane truck for the purpose of fall prevention and vibration suppression of a machine body during work, improvement of static stability during a heavy load, and the like. The counterweight is attached to and detached from the machine body, for example, during transportation of the construction machine and during replacement of a work device mounted on the machine body. In order to facilitate the attachment and detachment of the counterweight, a moving device that moves (lifts and lowers) the counterweight between the ground and the height (a mounting position) of the machine body is sometimes provided in the construction machine.
As the moving device for the counterweight, a moving device including a lifting and lowering mechanism (a link mechanism) including an arm member and a cylinder for lifting and lowering has been known. For example, a device of Patent Literature 1 includes a turning arm (an arm member), one end of which is pin-coupled to the rear end side of a revolving frame (a machine body frame), and a cylinder for lifting and lowering that turns the turning arm in the vertical direction. The device extends and retracts the cylinder for lifting and lowering to thereby turn the turning arm and move a counterweight, which is suspended at the other end of the turning arm, in an arc shape.
Incidentally, the counterweight configured to be detachably attachable is mounted (fixed) on a machine body by fastening a bolt to an attachment surface (e.g., an abutting plate of Patent Literature 1), which extends in the vertical direction at the rear end portion of the machine body frame, in the horizontal direction from the back toward the front of the machine body. At this point, when the counterweight is supported by only the bolt extending in the horizontal direction, the total load of the counterweight acts on the bolt in the shearing direction. Therefore, there is a concern about strength. As measures against this concern, there has been proposed a configuration in which a part for supporting, from the downward direction, the counterweight mounted on the machine body frame is provided on the machine body frame side and the load of the counterweight is supported by a portion other than the bolt as well (see, for example, Patent Literatures 2 and 3).